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Experimental Evidence for s-Wave Pairing Symmetry in Superconducting Cu_x}Bi_2}Se_3} Single Crystals Using a Scanning Tunneling Microscope

Published

Author(s)

Niv Levy, Tong Zhang, Jeonghoon Ha, Fred Sharifi, Alec Talin, Young Kuk, Joseph A. Stroscio

Abstract

Topological superconductors (TS) are a newly predicted phase of matter which is topologically distinct from conventional superconducting condensates of Cooper pairs. As a manifestation of its topological character, TS supports massless itinerant quasi-particles on the boundary, which are solid-state realizations of Majorana fermions. The recently discovered superconductor CuxBi2Se3 has been theoretically proposed as an odd-parity superconductor in the time-reversal-invariant TS class. Here we report scanning tunneling spectroscopy (STS) measurements of the superconducting energy gap in CuxBi2Se3 as a function of spatial position and applied magnetic field. The tunneling spectrum shows that the density of states at the Fermi level is fully gapped without any in-gap states. The spectrum is well described by the Bardeen-Cooper-Schrieffer (BCS) theory with a momentum independent order parameter, which strongly suggests that Cu0.2Bi2Se3 is a classical s-wave superconductor contrary to previous expectations.
Citation
Physical Review Letters
Volume
110
Issue
11

Keywords

Topological superconductors, scanning tunneling microscopy, scanning tunneling spectroscopy

Citation

Levy, N. , Zhang, T. , Ha, J. , Sharifi, F. , Talin, A. , Kuk, Y. and Stroscio, J. (2013), Experimental Evidence for s-Wave Pairing Symmetry in Superconducting Cu_{x}Bi_{2}Se_{3} Single Crystals Using a Scanning Tunneling Microscope, Physical Review Letters, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=912712 (Accessed January 26, 2022)
Created March 11, 2013, Updated October 12, 2021